No heat in vehicle

I just recently had the water pump changed and the thermostat, i also had new anti-freeze put in. So the vehicle does not over heat any more, but I can not get any heat to blow inside the vehicle. I turn on the heater and raise the temperature to 90 and all i get is cold air being blown into the car.
I had the radiator checked and the heater coil they are both fine. So the only thing I can come up with ts the actual temperature control unit. There is air blowing in but not hot air only cold. Also the hoses in the engine area are hot so there should be hot air. I was told that there is some type of door which the temperature control unit operates. It will open the correct door to let in cold or hot air. Is this true? And is there anyway to fix this problem? Do i need to purchase a new temperature
control unit? Or is there anyway to fix this problem? Or is there any way to diagnose this temperature control unit to see if this is the problem? Or do you know what the problem is? Thank you so much. I am in great need of help I live in NYC and it is very cold right now. Any help you can give me will be highly appreciated. Thank you Willie9433

Thank you for your help at least I now know what the problem is. Now can you tell me exactly where this part is located at? and how much is the price on this little motor that needs to be replaced? (any ball park figure will be great) Or any idea how much a mechanic will charge me to fix this problem? Thank you so much for your helpThank you for your help at least I now know what the problem is. Now can you tell me exactly where this part is located at? and how much is the price on this little motor that needs to be replaced? (any ball park figure will be great) Or any idea how much a mechanic will charge me to fix this problem? Thank you so much for your help

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Re: No heat in vehicle

There is a door that moves to control air temp from the heater core and AC evaporator core, it is the air temp control blend door , the door can stick and cause this or the little electric motor can fail, the electric stepper motor is much more common, I worked as a tech for a large Ford dealer for 20 years so I am sure of this diagnosis.
To cut to the quick of this, u must remove the dash assembly to replace this little motor, a 10-12 hour job for a pro, all day and into the night for a shade tree. Sorry for the bad news, but at least u know what the problem is.

approx center of dash area on the outside of the air duct work (dash removed of course) near the heater core, part is dealer only item, cost is about $45.00, like i said labor around $1000.00 US approx center of dash area on the outside of the air duct work (dash removed of course) near the heater core, part is dealer only item, cost is about $45.00, like i said labor around $1000.00 US

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Pressure test the radiator for leaks if it holds pressure start the engine. And check if pressure rises and keeps rising ,if it does it points to blown gasket or cracked head. A faulty thermostat can make it over heat so check it out . I would not mix the anti freeze as a lot of them don't mix well. put the anti freeze in all year as it stops corrosion of the cooling system.

Your posting does not indicate if you have a good clean mixture of antifreeze coolant in your heat & cool exchanger ( ie. radiator ), this valuable component of the vehicle coolant & heating system alway's need's a good supply of 50% water to 50% antifreeze which is under pressure and could hurt you or anyone standing too close to your vehice in question.

Purchase the anti-freeze in either full mixture (100%) or 50% water 50% anti-freeze just about anywhere out there with a vehicle repair isle. Personally speaking I mix 50% water 50% anti-freeze since this is much cheaper than buying the already 50% water to 50% anti-freeze simply due to economic reasons. After filling this radiator container, remember to alway's follow your vehicle manufacture's safety guidelines, remember there are many moving parts in the engine compartment that could hurt you or people standing around your vehicle while the engine is running.

Check your coolant level. It may be low.
Did they put the proper mixture of anti-freeze back in? I would have the anti-freeze checked. Or you can buy a simple little tool for a few bucks and do it yourself.

A radiator hose is supposed to be "hard" to withstand the heat. If hoses become soft it is time to replace them.

I don't know enough about Mercedes to answer your question much further other than to suggest the thermostat. If they put in a new radiator, they should have suggested putting in a new thermostat also, but they don't always do that.

put a 50/50 mix. remove radiator cap when cold,start car let run 1 min and dump 50/50 mix till full, a little will come out cap when thermostat opens this is normal,when thermostat opens coolant will go down,continue to fill till full,put cap on and fill reservoir to cold mark,check reservoir after you run a day and fill if needed to the full cold mark again

It depends on what reason you want the vehicle to reach 160 degrees. It seems 160 would be high to run a vehicle at. Nevertheless, if the mixture of anti-freeze and water at the correct mixture. If the mixture is not correct and it is more water than anti-freeze this will effect the heating temperature of the coolant.